//	Ex643-correct.cc

//	Sec. 6.4 of lecture
//		Dynamic arrays in structures

//	Demonstration of   c o r r e c t    code
//		wrt. copying a structure with pointers

#include <iostream.h>
#include <iomanip.h>			// setw
#include <strings.h>			// strcpy, strlen

struct Student2
  {
    long long int matrikel;
              int skz;
              char *pname, *pvorname;	// Pointers in structure
  };

main()
{
 Student2 arni, robbi;
 char     tmp[20];			// temp. input string

//	---------------------------------------------------------------
//		Input pvorname

 cout << endl << " Vorname : ";
 
//		setw guarantes that not more than 20 characters are read
//			see Schader/Kuhlin, p.96

 cin  >> setw(sizeof(tmp)) >> tmp;
 
//		Allocate memory for arni.pvorname

 arni.pvorname = new char[strlen(tmp)+1];
 strcpy(arni.pvorname,tmp);		// and copy input on it

//	---------------------------------------------------------------
//		Input pname

 cout << endl << " Familienname : ";
 cin  >> setw(sizeof(tmp)) >> tmp;

//		Allocate memory for arni.pname

 arni.pname = new char[strlen(tmp)+1];
 strcpy(arni.pname,tmp);		// and copy input on it

//	---------------------------------------------------------------
//		Input skz

 cout << endl << " Studentenkennzahl : ";
 cin >> arni.skz;

//	---------------------------------------------------------------
//		Input matrikel

 cout << endl << " Matrikelnummer    : ";
 cin >> arni.matrikel;

//	---------------------------------------------------------------
//	correct copying

 robbi = arni;	// copies int, long long int, int*
 		// but pvorname, pname point on dynamical data are posessed by arni
		// ===> allocate dynamical memory for robbi 
		//      (=>redefinition of pvorname, pname)

//		Allocate memory for robbi.pname

 robbi.pname = new char[strlen(arni.pname)+1];
 strcpy(robbi.pname,arni.pname);		// and copy input on it
 
//		Allocate memory for robbi.pvorname

 robbi.pvorname = new char[strlen(arni.pvorname)+1];
 strcpy(robbi.pvorname,arni.pvorname);		// and copy input on it

//	---------------------------------------------------------------
//				output robbi

 cout << endl << "-------- This output is still correct -----------" << endl;
 cout << robbi.pvorname << " "   << robbi.pname    << ", SKZ: ";
 cout << robbi.skz      << "   " << robbi.matrikel << endl << endl; 

//	---------------------------------------------------------------
//		Now, we deallocate dynamical data in arni

 delete [] arni.pvorname;
 delete [] arni.pname;
 
//	---------------------------------------------------------------
//				output robbi

 cout << endl << "-------- Even this output will be correct -----------" << endl;
 cout << robbi.pvorname << " "   << robbi.pname    << ", SKZ: ";
 cout << robbi.skz      << "   " << robbi.matrikel << endl << endl; 

//	---------------------------------------------------------------
//			Let us allocate in init some tiny dynamical array
 char *tiny;
 tiny = new char [5];
 strcpy(tiny,"tiny");

//	---------------------------------------------------------------
//				output robbi
//	Suddenly, robbi.pname == "tiny"

 cout << endl << "-------- Hey, nothing happend to my output!! -----------" << endl;
 cout << robbi.pvorname << " "   << robbi.pname    << ", SKZ: ";
 cout << robbi.skz      << "   " << robbi.matrikel << endl << endl; 

//	---------------------------------------------------------------
//		Now, we deallocate dynamical data in robbi

 delete [] robbi.pvorname;
 delete [] robbi.pname; 
}